Is it permissible to accept what a worker from a neighboring farm brings of its produce, if he offers it on his own initiative and of his own free will?

If what the farm worker brings you is his property, or if he is authorized by the farm owner to donate it, then there is no harm in accepting it; for the Prophet, peace and blessings be upon him, said: "The property of a Muslim person is not lawful unless given with his willing consent." If it is not clear whether it is rightfully his or not, then it is better to abstain from it as a precaution.